Bomb rack



pri l?, E945. o. YORK ETAL BOMB RACK Filed Jan. 4, 1941 Mum AT TORNE YS.

Patented Apr. i7, 1945 BOMB RACK Jones 0. York andvJ ames C. Winslow, Inglewood, Calif., assignors to Northrop Aircraft, Inc., Hawthorne, Calif., a corporation of California Application January 4, 1941, Serial No. 373,068

(Cl. 8f3-1.5)

4 Claims.

This invention relates to racks for carrying aircraft bombs. Among its objects are: To provide a rack of minimum weight and maximum carrying capacity; to provide a rack which will hold a bomb securely until its release is desired, and then will give a positive release; to provide a rack which may be released either mechanically or electrically and wherein a number of racks may be connected together, again either mechanically or electrically, to give simultaneous release or wherein the release may be achieved either individually or separately; to provide a rack wherein the bombs may normally be carried safe, and which will, if operated under emergency conditions, drop the bombs still inthe safe condition, but which is provided with a trip which may be operated either electrically or mechanically and which will, lwhen operated, arm thev bombs so that they will detonate on impact or upon the operation of a time fuse; to provide a rack which is adapted for operation with the bomb selector mechanism described in our copending application, Serial No. 373,069, led Jan. 4, 1941, by means of which the racks may be operated and the bombs dropped either simultaneously from all racks or in any desired order from individual racks or groups of racks, and to provide a plunger latch mechanism of simple construction and positive action whereby the arming and releasing operations can be accomplished with small application of energy even where the load carried by the rack is very large.

Other objects of this invention will be apparent or will be specifically pointed out in the description forming a part of this specication, but we do not limit ourselves to the embodiment of the invention herein described, as various forms may be adopted within the scope of the claims.

The invention may best be understood by reference to the accompanying drawing wherein:

Fig. 1 is a longitudinal sectional view of a rack embodying our invention, the plane of section being vertical.

Fig. 2 is a transverse sectional View through the rack, the plane of section -being indicated by the line 2-2 of Fig. 1.

Fig. 3 is a fragmentary view, partly in section, showing the mechanism of the release plunger.

Fig. 4 is a similar View showing one form of arming mechanism, adapted for electrical operation.

Fig. 5 is a fragmentary sectional View of alternative form of arming mechanism adapted for manual control.

In its preferred form the rack comprises a frame formed as an extruded section of light, high tensile strength alloy, such as dural or the newer The shape of this section is magnesium alloys. best shown in Fig. 2. In form it is a deep, narrow channel, comprising a top iiange I, from which depend side plates 2. The top flange is preferably provided with extensions on either side of the two dependent side plates, to provide means whereby the rack may be bolted or clamped to any desired form of supporting structure. The side plates 2 are each provided with an internally projecting concave rib 3, which ribs are opposed to form between the two side plates an interrupted cylindrical opening, between which certain cylindrical elements of the mechanism may be clamped and firmly held in place as will later be described. c

Pinned or otherwise secured to the extruded frame are two end plates Il, each comprising a cover plateV 5 whose edges conform to the outer outline of the section, from which a flange 'I projects conforming to the inner channel and positively positioning the plates. There is also provided a lower cover plate 9 for housing the rack mechanism completely, except for the necessary gaps ID, I0', and II to which the necessary connections are made between the bomb `and the operating mechanism of the rack.

Each of the side plates 2 is provided with a pair of rectangular notches I2, I2 which are spaced to receive the standard carrying lugs of .a bomb, these lugs being equally spaced irrespective of the sizeof the bomb to be carried, and there are preferably provided striker plates I3 of hardened steel which are riveted or otherwise secured to the side plates 2 on either side of the notches to protect the sides of the same from battering by the bomb lugs,

The actual support of the bomb is by a pair of hardened steel hooks I4 and I5, which are journaled on shafts I'I and Il', mounted between the side plates. These shafts are both adjacent to their respective notches I2, I2', but displaced to one side thereof, so that the weight of the bomb tends to rotate the hooks I4 and I5permitting the bomb to drop. The hooks respectivelyl carry extensions I9, 2U, projecting above their pivotal mountings and'acting as lever arms to which links 2l are pivoted, the links 2| connecting the two hooks so that their. movement is in unison and both of the bomb lugs, when released, will be released simultaneously.

Extension or lever Varm I9 of the hook I4 (which may be termed the master hook) is formed as a sector or plate extending forward,

over the notch, so as to form a striker plate which contacts the bomb lug upon loading a bomb and automatically latches the bomb rack. The extreme tip of the forward extension has an approximately Vertical or slightly backwardly sloping surface (as considered with the hook in the loaded position) beneath which is a face I8 which slopes back, towardthe pivotal, mounting.- o the hook, at anoblique-angle. A hardenedsteel sear 22, pivotally supported between the side plates on a shaft 23; is provided'with a face 24 which conjugate to and engages the face I8 of the sector I9, plus an extension which engages theip@ of the sector and prevents thesear. fromialling toward the notch. The shaftg, 23 isloatedneara the lower edges of the side platesandbeyondthe. greatest dimension of the sector I9, so that when the hook I4 is in the loaded.i position the'searA slopes toward the sector with the face 24 engaged with the sector. This disposition of the parts results.y in the: maximum/stress. imposed upon` the sear by the tendency?offtheihook-to rotate-under the-weight ofrthebomb-Jbeing longitudinal ofi'the sear. The `oblique nface I 8 lof theA sector; however; doeslexertaxcamming. action which tendslto ro. tatethe scar on itsshaft, but'tl'ietangentialmo` mentfthusirnposed is:relativelysmall in compari-1 sontotheweight offthebomb, both bysreason of: the greaterfleverf arm of'k the sear-than that-'off the bomb with` respect: to. the shaft1 I13v andl be.Y cause: of?V the. direction` of-fthe. line ofi' application offthe-,forcelagainstthesear; Byy alminor altera-- tion=of the design, changingftheobliquityofthefaces I8i and 24; the: relativemagnitudefof 'the-radial` (or. longitudinal) force on'. the f sear' and the tangential forcer which: tends` to disengagel they sear, may be varied at will.

The sean is held; in. engagement.' with thefsector -I Stbyatspring 1plur'igersdesignated'bythe gen-U eral: reference character'.4 25';l The detailed struc` ture-,of thiszplungenis showniniEig; 3; Itfcorn'-` prises` a=,hardeneds steelt housing; or.-- cylinder 2:1v whiclri-.isv provided .with-,flanges-Z 9;-andw30f of such` diameter.. as to- 't the#4 channel formed= between -l the'rribszf. A pair` Qf:transverse groovesy 3I. are` formed; in the; ange-f, for; receiving f a pair off cross: bolts: 32 whichV pass: through theframe. transversely andl clamp .the lhousing-21 posi tion'.

Withinthe-housing a." cylindricalboreS-g withinI which `slides-a domedlhardened' steelI cap` 3.4;' The: domeLof-'thecapmerges with 1a-cylindri cal zsleeve; provided-'withv a number--v ofi radial per forationsQW-hich areoffsucli -sizegasI to 'receive easi# lyan equal number-of steelballs tl'ieseeballsy beingi of such size-that theirl radiusy isnearlyff equal to theA thickness l ofl the `wall of the-cap.`

When the plunger is in the advanced-position shown in the drawing; with i the= cap 34' bearing against; the sear- 22;l thegballs 35 .seatrina semitoroidal groovedormed Within theilangeSIlf-of Movement of fthe' balls 35i-'witloof l such diameter` as to slide'ireelylwithin Lthe cap radius connecting withv the: mainbodyof.- theplunger -by'asloping shoulder'.` Thel reductioirin radiusof `tlfie'tipis substantially equal 'to the-rw dius-of ther-balls-35gu and lit follows that ywhen'the-L plunger 31 is fully advanced within the cap 34 the main diameter of the plunger holds thev balls seated within the groove. If, however, the inner plunger be retracted, force from the sear applied against the end of the cap will tend to roll the balls out of the groove and back into the recess formed by the reduced tip 42. When the balls are seated against the,groovetheyi arestressed almost purely in' shear. andA ther cap.n is firmly latched in position, but with the balls forced inward against the tip 42 the cap is free to slide within the housing, permitting the sear to drop back-and release the hook I4 and consequently, the hook 4lwhich is linkedthereto.

The,end;of the plunger 31 extends through the end'4'I.v oftleliousng and carries across pin 44 which slides in a slot 45 in a release link 41. This releaseflinkis-.inm theform of a yoke with one arm extendinglon either side of the plunger 31. The other end of the link is mounted on a rod 49, whichizmay/be either.;integraliwithaor; connect'edlto theiplunger armatureiof solenoidjz. Arspringf, 5 I1 normallyH urges solenoid: anrhlink: toward; the.

' plunger: 31,- and.` against aistop'. formed.. by: az, dee.-

pending.: arm 52 whichzisfintegratwithzth link4 and: engages:aihalf. round shatsm journaledrin.

the sideiplatesoi'.

Connection. to-v the;- solenoidis madef, through; aymultiple plug 54; Whenstheacircuitto theisolef noid-fisi. closedxits .plunger-,f is:y attracted; .sliding; the. link 4in-.backward -alongatiienpiny 44? until' thelatter-r reachesY the l end forthe, slot-,45: atiwhich tin'leathef armaturen and: linka have` acquired:v amconsiderab1emomentum; striking.` a; hammer: blow.y against.:theA pinand thus retractingtheiplungerl, permittihzf thexballs; 35' to fallfinv againstthe eplunger.:` tip42; and :therebycperm'uztir'1g.` the=oapz3 4::a'lsoi to' retract: andlreleasejtheseanandftliusnthe hooks I 4* @andi I 5.'

This"` actioni issextremelyvpositive: The@ entirev bomb rack, includingftlie parts yet-Lto-bedesoribed; weighs `less s than 1 six; pounds; Itvhas been'v tested 2 under loads as'` high asL thirty-fiveA hundred` pounds',v and-'hasbeen found to holdfsuclialoads safely-andito release 'them' positively. 'I'hefxnaxi-i Y mum-force exerted'lbetweem the-link 41' andlthe` pounds; and Jsince zthis vforce is-securedt b'y-impact the.; maximumpull exerted* bylv the solenoidisl greatlyless-Ythanftliis, i5 ef, of thee order-'offvepounds:-

In=case= ofl damage to A' the-electrica1 system; or if desired for any other reason; ,handreleaswmay befeffectedby rotating the slant/1531,"whiclris proa vided =Witli =afhandflever 55lfr-the'fpurposey tli'ereeby'V exerting a'4 cammingf-action' against the amv 52-vl of the linkw and so"4 retractingA they r plunger 31"" as4` inV the case= of; electrical operation: lBcamkfl racksfvarel customarily-mountedfsideby-side; andw1 it is therefore" possibler tor extend* their shaft 53 through-a^ number'off adiacenti-racks; onto-use" separate; shafts -531'andi intereconnect them `f with flexible'couplingsf` sol thatfafllort any` vdesiifednlnuxxrber of racks may be made to releaseltheirlads simultaneously:

In order;N tosupervise theA electrical' operation" of the rack, particularly whenoperated in corrnection '-witlizthe selec-torA systemof Pour' copending application'V above referred to; thereis-fprovideda normally openpushibutton switch 51-T which'is depressed f and closed byfan= arcuate 1flug Av60 onthei' extension 20 o the hook I5 when the raekfisf loaded. When td'iebon'ibv isrel'easedithe lprojection and lug. move? forward? 'allowing` they, switcliiv toi open. In practice itis connected.throughsoneeoff the, contacts; ofgtheff plugs :B 54S to ia'r, pilot flizhti as the circuit to the electromagnet is closed the shown in the copending application, which is thus extinguished to indicate that its-corresponding rack is empty. 4

Although the primary function of a bomb rack is to carry the bombs and release them at will, there is also the necessity of arming the bombs before they are dropped. It is an almost universal practice to carry the bombs in a safe condition. Whether they be provided with time or percussion fuses, these fuses are normally held inoperative by a screw on which a small propeller or air screw is mounted. The screw is threaded into either the nose or the tail of the bomb, or, in some instances, both.

The propeller and screw are held from turning by a wire when the bomb is in safe condition. If the wire be withdrawn before the bomb is dropped, the propeller will rotate until the screw is withdrawn, after which propeller and screw will drop olf and the bomb will continue its night with the fuse in active condition. If the wire'be not withdrawn before the bomb is released the screw cannot turn, and the bomb will therefore not explode upon landing. Means are therefore provided for so holding the arming wire that should it be necessary to relase the bomb before a military objective is reached the wire will pull clear to travel with the bomb upon its flight and the bomb will therefore drop in safe condition. When, however, a tactical release of the bombs is desired the arming wire is held tightly when the bomb is dropped and the bomb, in falling, pulls the wire clear so that the bomb falls armed. The mechanism for accomplishing this is shown in detail in Figs. 4 and 5. In the form of the device shown in Fig. 4 the arming is done electrically. The device comprises a block 6|, having a longitudinal bore 62 therethrough within which a pair of balls 63 and 64 t freely. A transverse slot 65 extends through the block 6l, intersecting the bore, and a pin 6l holds the ball 63 so that its contact with the ball 64 occurs within the range of this slot. The ball 64 is urged against ball 63 by a plunger 69 urged by a spring 70. A

loop of the arming wire may therefore be thrust through the opening Il in the lower cover plate 9 of the rack and the slot 65, and the ball 84 will snap back readily to permit its passage, and if the bomb be released with the arming mechanism in this condition the loop will pull out just as readily and permit the bomb to drop safe Means are provided, however, for locking the plunger 69 so that lt cannot thus yield to permit release of the arming wire. Locking of the plunger is accomplished by the application of the same principles as those used on the bomb release mechanism itself. The plunger 69 has a sloping shoulder and reduced diameter end similar to those of the plunger 3l, and the reduced end of the plunger extends into a sleeve il, integral with the block 6|. Balls l2 are carried in perforations in this sleeve, and rest against the sloping shoulder, and are held in place by a ferro-magnetic cap 'i3 which ts over the sleeve and rests against the block 6l, urged into that position by a spring lll. When the cap 13 is in this position the balls are forced outwardly into the semi-toroidal groove l within the cap when the arming wire is slipped between the balls 63. and 65. The cap 73 forms the armature of electromagnet 11, carried by a mounting block 'i9 to which the plug 54, solenoid Eil, and switch 5l are also secured. Circuit to the electromagnet 'l1 is completed through another of the contacts of the plug 54 and when armature is attracted, which forces the balls 12 out of the groove 'I5 and tightly against the shoulder of the plunger 63, so that it cannot move to release the arming wire. Accordingly, when the magnet TI is excited prior to or simultaneously with the actuation of the release, the arming wire will be retained and the bomb dropped armed.

Where electrical equipment is not available, and it is desired to use a mechanically operated armed-and-safe mechanism, the device of Fig. 4 may be modied as shown in Fig. 5. The balls B3 and 64 are carried in a bore in a block 6l'. similarly to the balls B3 and Sil of Fig. 4. A

shaft having a flattened' surface 8l extendsA through the block. When thisshaft is so rotated that the flat surface is presented to the ball 63', the ball 64 is held in Contact with ball 63 by a spring B2, and the loop of the arming wire can be slipped in and out in the same manner as in the previously described device. When the shaft 80 is turned to the position shown, however, the ball 63 is forced against ball 64', compressing the spring 32 until the ball 64' hits a stop 83, and when this condition obtains the arming wire is tightly locked in place and will accordingly pull out of the bomb and arm the latter when it is released.

It will be obvious from the foregoing description that in the case of electrical operation the circuits involved are each of the simple series variety. A common exciting battery may, of course, be used, but from this battery the circuits Inay simply include a switch and the respective magnets or pilot lights, and it is therefore believed unnecessary to show a wiring ,diagram here, particularly as the more complicated selector circuits are shown in detail in our above mentioned copending application.

We claim:

l. A bomb rack comprising an extruded structural section having the form of a channel with a pair of opposed concave ribs on the inner surfaces of the flanges thereof, said flanges having notches inthe edges thereof adapted to receive the carrying lugs of a bomb, a pair of bomb supporting hooks pivotally mounted between said flanges beside said notches and movable to close said notches, a link connecting said hooks to compel movement thereof in unison, a lever arm on one of said hooks, a Sear engaging said lever arm, and retaining and releasing means for said sear clamped between the concave faces of said ribs.

2'. A bomb rack comprising an extruded structuralsection having the form of a channel with a pair of opposed concave ribs on the inner surfaces of the flanges thereof, said flanges having notches in the edges thereof adapted to receive the carrying lugs of a bomb, a pair of bomb supporting hooksA pivotally mounted between said flanges beside said notches and movable to close said notches, a link connecting said hooks to compel movement thereof in unison, a lever arm on one of said hooks, a sear engaging said lever arm, and a plunger latch including a housing cylinder, bearing against said sear, the cylinder of said latch being clamped between the concave faces of said ribs.

3. In a bomb release mechanism having a bomb carrying hook held in position against the weight of a bomb by a self-releasing sear and a sear control assembly, said sear control assembly comprising a stop for engagement with said sear; to: hold the.: same; againstY release,, a:4 plunger; holding;v saldi stop in; engagement; Wit-h: said sean, and: meansr for. withdrawing said plungen from: its.. stop holding postiom, said means. including af. pin: and slot-,1- connectionyto: said plunger. with saidz pin.:rtformalbL-fy ini` spacedf. relationship' to: the engageable-A end; on said*v slot..v to,` eiect. av suddeni Withdrawal: of; said?. plunger: in response to operation of said plunger?" Withi-F drawal means.

4. A bomb. rack fon handling; bombsf equllled: with removable: arming; dewices-,, saickbomn rack comprising a frame including agpain'ofz'sidezplates: each providedwithapair of! notches adapted to'.l

memos@ hooked to: compel their:mow-:ment.-inunison, said., hooks; bein@ movable; to.A close,l said` notches.` to.u retainsaid lugs, a selfreleasng sean pivoted.

from; its: holdingv position; meansV for` releasing said. stopft'o. releasefsaid.. sean audio. free said, hooks,1,.a; holding` means; mounted: on,- sad frame for; engaging the aforesaid arming devices of thee:` bombs?. and means mounted:v on said.. frame,` .togselectivelw control: said holding means-- simul.- `caneously with said releasing meansdzo releasev receive they carrying lugsbf; the bombnzpanof: 1f saich bombsf/W'ltlr.;o1"Withouinsadfarmingi devices.

hooks pivotally mounted. betxaveenV said-r side:- platesf; adjacent ,to said notched, a1 link` connectin'gf. said',

.IQNES' 0.. YORK.. JAMES'L G. WINSLOW; 

